Neon solar system

By its great mass, the Sun constitutes the major part of the Solar System. In this sense, it is more representative than the planets, which have been the scene of intensive chemical fractionation. The composition of the solar photosphere can thus be compared with the contents of meteorites, stones that fall from the sky, a second source of information on the composition of the protosolar cloud, provided that volatile elements such as hydrogen, helium, carbon, nitrogen, oxygen and neon are excluded. Indeed, the latter cannot be gravitationally bound to such small masses as meteorites and tend to escape into space over the long period since their formation. 

Neon is the fifth most abundant element in the universe. Its second most abundant isotope, 22Ne, is the 13th most abundant isotope in the universe, placing it between 3He and 2 Mg in rank. From the isotopic decomposition of terrestrial neon one finds that the mass-22 isotope, 22Ne, is 6.79% of all Ne isotopes. Using the total abundance of elemental Ne = 3.44 million per million silicon atoms (i.e. 3.4 times more abundant than Si) in solar-system matter, this isotope has... 

Neon in planetary atmospheres is isotopically heavier than the solar composition, and falls within meteoritic values. Neon-isotopic compositions for the atmosphere and solar system reservoirs are shown in Figure 2. The greatest differences between solar system bodies are seen in the proportions of Ne and Ne, which are not produced in significant quantities in large bodies. The value of NePNe = 13.8 0.1 (Benkert et al., 1993 Pepin et al., 1999) derived for the solar wind is believed to represent the initial... 

These predictions, based on the composition of early rocks, are supported by a second line of evidence, which provides a clue to the origin of this early atmosphere. This is the rarity of inert unreactive gases, particularly neon, in the Earth s atmosphere today. Neon is the seventh most abundant element in the Universe. It was abundant in the clouds of dust and gas from which the Earth and the other planets of the Solar System condensed. As an inert gas, neon is even more unreactive than nitrogen. If any of the Earth s original atmosphere had survived the meteorite bombardment, it should have contained about the same amount of neon as nitrogen. In fact, the ratio of neon to nitrogen is 1 to 60000. If there ever had been a Jupiter-like atmosphere on Earth, then it must have been swept away during that first ferocious period of meteorite bombardment. 

Whitby J, Burgess R, Turner G, Gilmour J, Bridges J (2000) Extinct in halite from a primitive meteorite Evidence for evaporite formation in the early solar system. Science 288 1819-1821 Widing KG (1997) Emerging active regions on the sun and the photospheric abundance of neon. Astrophys J 480 400-405... 

Hutchins KS, Jakosky BM, Luhmarm JG (1997) Impact of a paleomagnetic field on sputtering loss of martian atmospheric argon and neon. J Geophys Res 102 9183-9189 Igarashi G (1995) Primitive Xe in the Earth. In Volatiles in the Earth and Solar System. Farley KA (ed). Am Inst Phys Coirf Proc 341 70-80... 

Jupiter is the largest planet within the solar system (Fig. 3.14). Its mass is 2.5 times the mass of all other planets in the solar system. Jupiter s atmosphere is composed of about 88-92% of hydrogen and 8-12% of helium. There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, methane, water vapor, ammonia, silicon-based compound and also phosphine and sulfur. Helium in the Jupiter atmosphere is depleted (compared with the composition of the primordial solar nebula). This can be explained by a precipitation of the helium into the interior of the planet. The composition of Saturn is similar to that of Jupiter, Uranus and Neptune have much less hydrogen and helium. 

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